The present invention is directed to the novel use of a peptide class of compound for treating different types and symptoms of acute and chronic pain, especially non neurophathic inflammatory pain.
Certain peptides are known to exhibit central nervous system (CNS) activity and are useful in the treatment of epilepsy and other CNS disorders. These peptides which are described in the U.S. Pat. No. 5,378,729 have the Formula (I): 
wherein
R is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, aryl, aryl lower alkyl, heterocyclic, heterocyclic lower alkyl, lower alkyl heterocyclic, lower cycloalkyl, lower cycloalkyl lower alkyl, and R is unsubstituted or is substituted with at least one electron withdrawing group or electron donating group;
R1 is hydrogen or lower alkyl, lower alkenyl, lower alkynyl, aryl lower alkyl, aryl, heterocyclic lower alkyl, heterocyclic, lower cycloalkyl, lower cycloalkyl lower alkyl, each unsubstituted or substituted with an electron donating group or an electron withdrawing group; and
R2 and R3 are independently hydrogen, lower alkyl, lower alkenyl, lower alkynyl, aryl lower alkyl, aryl, heterocyclic, heterocyclic lower alkyl, lower alkyl heterocyclic, lower cycloalkyl, lower cycloalkyl lower alkyl, or Z-Y wherein R2 and R3 may be unsubstituted or substituted with at least one electron withdrawing group or electron donating group;
Z is O, S, S(O)2, NR4, PR4 or a chemical bond;
Y is hydrogen, lower alkyl, aryl, aryl lower alkyl, lower alkenyl, lower alkynyl, halo, heterocyclic, heterocyclic lower alkyl, and Y may be unsubstituted or substituted with an electron donating group or an electron withdrawing group, provided that when Y is halo, Z is a chemical bond, or
ZY taken together is NR4NR5R7, NR4OR5, ONR4R7, OPR4R5, PR4OR5, SNR4R7, NR4SR7, SPR4R5 or PR4SR7, NR4PR5R6 or PR4NR5R7, 
R4, R5 and R6 are independently hydrogen, lower alkyl, aryl, aryl lower alkyl, lower alkenyl, or lower alkynyl, wherein R4, R5 and R6 may be unsubstituted or substituted with an electron withdrawing group or an electron donating group; and
R7 is R6 or COOR8 or COR8;
R8 is hydrogen or lower alkyl, or aryl lower alkyl, and the aryl or alkyl group may be unsubstituted or substituted with an electron withdrawing group or an electron donating group; and
n is 1-4; and
a is 1-3.
U.S. Pat. No. 5,773,475 also discloses additional compounds useful for treating CNS disorders. These compounds are N-benzyl-2-amino-3-methoxy-propionamide having the Formula (II): 
wherein
Ar is aryl which is unsubstituted or substituted with halo; R3 is lower alkoxy; and R1 is lower alkyl especially methyl.
The patents are hereby incorporated by reference. However neither of these patents describe the use of these compounds as specific analgesics for the treatment of acute and chronic pain, especially rheumatic inflammatory pain. Particularly the antinociceptive profile and properties of this class of compounds are not disclosed.
Accordingly, the present invention relates to the novel use of a compound having Formula (I) and/or Formula (II) showing antinociceptive properties for treating different types and symptoms of acute and chronic pain, especially non neuropathic inflammatory pain.
Particularly the present invention concerns the use of said compounds of Formulae (I) and/or (II) for the preparation of a pharmaceutical composition for the treatment of different types and symptoms of acute and chronic pain, especially non neuropathic inflammatory pain. This include chronic inflammatory pain e.g. rheumatoid arthritis pain and/or secondary inflammatory osteoarthritic pain.
A compound according to the invention has the general Formula (I) 
wherein
R is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, aryl, aryl lower alkyl, heterocyclic, heterocyclic lower alkyl, lower alkyl heterocyclic, lower cycloalkyl, lower cycloalkyl lower alkyl, and R is unsubstituted or is substituted with at least one electron withdrawing group, or electron donating group;
R1 is hydrogen or lower alkyl, lower alkenyl, lower alkynyl, aryl lower alkyl, aryl, heterocyclic lower alkyl, heterocyclic, lower cycloalkyl, lower cycloalkyl lower alkyl, each unsubstituted or substituted with an electron donating group or an electron withdrawing group; and
R2 and R3 are independently hydrogen, lower alkyl, lower alkenyl, lower alkynyl, aryl lower alkyl, aryl, heterocyclic, heterocyclic lower alkyl, lower alkyl heterocyclic, lower cycloalkyl, lower cycloalkyl lower alkyl, or Z-Y wherein R2 and R3 may be unsubstituted or substituted with at least one electron withdrawing group or electron donating group;
Z is O, S, S(O)2, NR4, PR4 or a chemical bond;
Y is hydrogen, lower alkyl, aryl, aryl lower alkyl, lower alkenyl, lower alkynyl, halo, heterocyclic, heterocyclic lower alkyl, lower alkyl, and Y may be unsubstituted or substituted with an electron donating group or an electron withdrawing group, provided that when Y is halo, Z is a chemical bond, or
ZY taken together is NR4NR5R7, NR4OR5, ONR4R7, OPR4R5, PR4OR5, SNR4R7, NR4SR7, SPR4R5 or PR4SR7, NR4PR5R6 or PR4NR5R7, 
R4, R5 and R6 are independently hydrogen, lower alkyl, aryl, aryl lower alkyl, lower alkenyl, or lower alkynyl, wherein R4, R5 and R6 may be unsubstituted or substituted with an electron withdrawing group or an electron donating group;
R7 is independently R6 or COOR8 or COR8;
R8 is hydrogen or lower alkyl, or aryl lower alkyl, and the aryl or alkyl group may be unsubstituted or substituted with an electron withdrawing group or an electron donating group; and
n is 1-4; and
a is 1-3.
Furthermore a compound according to the invention has the general Formula (II) 
wherein
Ar is aryl which is unsubstituted or substituted with halo; R3 is lower alkoxy; and R1 is lower alkyl, especially methyl.
The present invention is also directed to the preparation of pharmaceutical compositions comprising a compound according to Formula (I) and/or Formula (II) useful for the treatment of rheumatic inflammatory pain.
As indicated hereinabove, the compounds of Formula I are useful for treating pain, particularly non neuropathic inflammatory pain. This type of pain includes chronic inflammatory pain e.g. rheumatoid arthritis pain and/or secondary inflammatory osteoarthritic pain. They show an anti-nociceptive effectiveness.
These compounds are described in U.S. Pat. No. 5,378,729, the contents of which are incorporated by reference.
As defined herein, the xe2x80x9calkylxe2x80x9d groups when used alone or in combination with other groups, are lower alkyl containing from 1 to 6 carbon atoms and may be straight chain or branched. These groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, amyl, hexyl, and the like.
The xe2x80x9caryl lower alkylxe2x80x9d groups include, for example, benzyl, phenethyl, phenpropyl, phenisopropyl, phenbutyl, diphenylmethyl, 1,1-diphenylethyl, 1,2-diphenylethyl, and the like.
The term xe2x80x9carylxe2x80x9d, when used alone or in combination, refers to an aromatic group which contains from 6 up to 18 ring carbon atoms and up to a total of 25 carbon atoms and includes the polynuclear aromatics. These aryl groups may be monocyclic, bicyclic, tricyclic or polycyclic and are fused rings. A polynuclear aromatic compound as used herein, is meant to encompass bicyclic and tricyclic fused aromatic ring systems containing from 10-18 ring carbon atoms and up to a total of 25 carbon atoms. The aryl group includes phenyl, and the polynuclear aromatics e.g., naphthyl, anthracenyl, phenanthrenyl, azulenyl and the like. The aryl group also includes groups like ferrocyenyl. xe2x80x9cLower alkenylxe2x80x9d is an alkenyl group containing from 2 to 6 carbon atoms and at least one double bond.
These groups may be straight chained or branched and may be in the Z or E form. Such groups include vinyl, propenyl, 1-butenyl, isobutenyl, 2-butenyl, 1-pentenyl, (Z)-2-pentenyl, (E)-2-pentenyl, (Z)-4-methyl-2-pentenyl, (E)-4-methyl-2-pentenyl, pentadienyl, e.g., 1, 3 or 2,4-pentadienyl, and the like.
The term lower xe2x80x9calkynylxe2x80x9d is an alkynyl group containing 2 to 6 carbon atoms and may be straight chained as well as branched. It includes such groups as ethynyl, propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl, 3-methyl-1-pentynyl, 3-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl and the like.
The term lower xe2x80x9ccycloalkylxe2x80x9d when used alone or in combination is a cycloalkyl group containing from 3 to 18 ring carbon atoms and up to a total of 25 carbon atoms. The cycloalkyl groups may be monocyclic, bicyclic, tricyclic, or polycyclic and the rings are fused. The cycloalkyl may be completely saturated or partially saturated. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclohexenyl, cyclopentenyl, cyclooctenyl, cycloheptenyl, decalinyl, hydroindanyl, indanyl, fenchyl, pinenyl, adamantyl, and the like. Cycloalkyl includes the cis or trans forms. Furthermore, the substituents may either be in endo or exo positions in the bridged bicyclic systems.
The term xe2x80x9celectron-withdrawing and electron donatingxe2x80x9d refer to the ability of a substituent to withdraw or donate electrons, respectively, relative to that of hydrogen if the hydrogen atom occupied the same position in the molecule. These terms are well understood by one skilled in the art and are discussed in Advanced Organic Chemistry, by J. March, John Wiley and Sons, New York, N.Y., pp.16-18 (1985) and the discussion therein is incorporated herein by reference. Electron withdrawing groups include halo, including bromo, fluoro, chloro, iodo and the like; nitro, carboxy, lower alkenyl, lower alkynyl, formyl, carboxyamido, aryl, quaternary ammonium, trifluoromethyl, aryl lower aklyanoyl, carbalkoxy and the like. Electron donating groups include such groups as hydroxy, lower alkoxy, including methoxy, ethoxy and the like; lower alkyl, such as methyl, ethyl, and the like; amino, lower alkylamino, di(loweralkyl) amino, aryloxy such as phenoxy, mercapto, lower alkylthio, lower alkylmercapto, disulfide (lower alkyldithio) and the like. One of ordinary skill in the art will appreciate that some of the aforesaid substituents may be considered to be electron donating or electron withdrawing under different chemical conditions. Moreover, the present invention contemplates any combination of substituents selected from the above-identified groups.
The term xe2x80x9chaloxe2x80x9d includes fluoro, chloro, bromo, iodo and the like.
The term xe2x80x9cacylxe2x80x9d includes lower alkanoyl.
As employed herein, the heterocyclic substituent contains at least one sulfur, nitrogen or oxygen ring atom, but also may include one or several of said atoms in the ring. The heterocyclic substituents contemplated by the present invention include heteroaromatics and saturated and partially saturated heterocyclic compounds. These heterocyclics may be monocyclic, bicyclic, tricyclic or polycyclic and are fused rings. They may contain up to 18 ring atoms and up to a total of 17 ring carbon atoms and a total of up to 25 carbon atoms. The heterocyclics are also intended to include the so-called benzoheterocyclics. Representative heterocyclicx include furyl, thienyl, pyrazolyl, pyrrolyl, imidazolyl, indolyl, thiazolyl, oxazolyl, isothiazolyl, isoxazolyl, piperidyl, pyrrolinyl, piperazinyl, quinolyl, triazolyl, tetrazolyl, isoquinolyl, benzofuryl, benzothienyl, morpholinyl, benzoxazolyl, tetrahydrofuryl, pyranyl, indazolyl, purinyl, indolinyl, pyrazolindinyl, imidazolinyl, imadazolindinyl, pyrrolidinyl, furazanyl, N-methylindolyl, methylfuryl, pyridazinyl, pyrimidinyl, pyrazinyl, pyridyl, epoxy, aziridino, oxetanyl, azetidinyl, the N-oxides of the nitrogen containing heterocycles, such as the nitric oxides of pyridyl, pyrazinyl, and pyrimidinyl and the like. The preferred heterocyclic are thienyl, furyl, pyrrolyl, benzofuryl, benzothienyl, indolyl, methylpyrrolyl, morpholinyl, pyridiyl, pyrazinyl, imidazolyl, pyrimidinyl, or pyridazinyl. The preferred heterocyclic is a 5 or 6-membered heterocyclic compound. The especially preferred heterocyclic is furyl, pyridyl, pyrazinyl, imidazolyl, pyrimidinyl, or pyridazinyl. The most preferred heterocyclics are furyl and pyridyl.
The preferred compounds are those wherein n is 1, but di, tri and tetrapeptides are also contemplated to be within the scope of the claims.
The preferred values of R is aryl lower alkyl, especially benzyl especially those wherein the phenyl ring thereof is unsubstituted or substituted with electron donating groups or electron withdrawing groups, such as halo (e.g., F).
The preferred R1 is H or lower alkyl. The most preferred R1 group is methyl.
The most preferred electron donating substituents and electron withdrawing substituents are halo, nitro, alkanoyl, formyl, arylalkanoyl, aryloyl, carboxyl, carbalkoxy, carboxamido, cyano, sulfonyl, sulfoxide, heterocyclic, guanidine, quaternary ammonium, lower alkenyl, lower alkynyl, sulfonium salts, hydroxy, lower alkoxy, lower alkyl, amino, lower alkylamino, di(loweralkyl)amino, amino lower alkyl, mercapto, mercaptoalkyl, alkylthio, and alkyldithio. The term xe2x80x9csulfidexe2x80x9d encompasses mercapto, mercapto alkyl and alkylthio, while the term disulfide encompasses alkyldithio. These preferred substituents may be substituted on any one of R1, R2, R3, R4, R5 or R6, R7 or R8 as defined herein.
The ZY groups representative of R2 and R3 include hydroxy, alkoxy, such as methoxy, ethoxy, aryloxy, such as phenoxy; thioalkoxy, such as thiomethoxy, thioethoxy; thioaryloxy such as thiophenoxy; amino; alkylamino, such as methylamino, ethylamino; arylamino, such as anilino; lower dialkylamino, such as, dimethylamino; trialkyl ammonium salt, hydrazino; alkylhydrazino and arylhydrazino, such as N-methylhydrazino, N-phenylhydrazino, carbalkoxy hydrazino, aralkoxycarbonyl hydrazino, aryloxycarbonyl hydrazino, hydroxylamino, such as N-hydroxylamino (xe2x80x94NHxe2x80x94OH), lower alkoxy amino [(NHOR18) wherein R18 is lower alkyl], N-lower alkylhydroxyl amino [(NR18)OH wherein R18 is lower alkyl], N-lower alkyl-O-lower alkylhydroxyamino, i.e., [N(R18)OR19 wherein R18 and R19 are independently lower alkyl], and o-hydroxylamino (xe2x80x94Oxe2x80x94NH2); alkylamido such as acetamido; trifluoroacetamido; lower alkoxyamino, (e.g., NH(OCH3); and heterocyclicamino, such as pyrazoylamino.
The preferred heterocyclic groups representative of R2 and R3 are monocyclic heterocyclic moieties the formula: 
or those corresponding partially or fully saturated form thereof wherein n is 0 or 1; and
R50 is H or an electron withdrawing group or electron donating group;
A, Z, L and J are independently CH, or a heteroatom selected from the group consisting of N, O, S; and
G is CH, or a heteroatom selected from the group consisting of N, O and S,
but when n is O, G is CH, or a heteroatom selected from the group consisting of NH, O and S with the proviso that at most two of A, E, L, J and G are heteroatoms.
When n is O, the above heteroaromatic moiety is a five membered ring, while if n is 1, the heterocyclic moiety is a six membered monocyclic heterocyclic moiety. The preferred heterocyclic moieties are those aforementioned heterocyclics which are monocyclic.
If the ring depicted hereinabove contains a nitrogen ring atom, then the N-oxide forms are also contemplated to be within the scope of the invention.
When R2 or R3 is a heterocyclic of the above formula, it may be bonded to the main chain by a ring carbon atom. When n is O, R2 or R3 may additionally be bonded to the main chain by a nitrogen ring atom.
Other preferred moieties of R2 and R3 are hydrogen, aryl, e.g., phenyl, aryl alkyl, e.g., benzyl and alkyl.
It is to be understood that the preferred groups of R2 and R3 may be unsubstituted or substituted with electron donating or electron withdrawing groups. It is preferred that R2 and R3 are independently hydrogen, lower alkyl, which is either unsubstituted or substituted with an electron withdrawing group or an electron donating group, such as lower alkoxy (e.g., methoxy, ethoxy, and the like), N-hydroxylamino, N-lower alkylhydroxyamino, N-loweralkyl-O-loweralkyl and alkylhydroxyamino.
It is even more preferred that one of R2 and R3 is hydrogen.
It is preferred that n is one.
It is preferred that R2 is hydrogen and R3 is hydrogen, an alkyl group which is unsubstituted or substituted by at least an electron donating or electron withdrawing group or ZY. In this preferred embodiment, it is more preferred that R3 is hydrogen, an alkyl group such as methyl, which is unsubstituted or substituted by an electron donating group, or NR4OR5 or ONR4R7, wherein R4, R5 and R7 are independently hydrogen or lower alkyl. It is preferred that the electron donating group is lower alkoxy, and especially methoxy or ethoxy.
It is also preferred that R is aryl lower alkyl. The most preferred aryl for R is phenyl. The most preferred R group is benzyl. In a preferred embodiment, the aryl group may be unsubstituted or substituted with an electron donating or electron withdrawing group. If the aryl ring in R is substituted, it is most preferred that it is substituted with an electron withdrawing group, especially on the aryl ring. The most preferred electron withdrawing group for R is halo, especially fluoro.
The preferred R1 is loweralkyl, especially methyl.
The more preferred compounds are compounds of Formula (I) wherein n is 1; R2 is hydrogen; R3 is hydrogen, an alkyl group, especially methyl which is substituted by an electron donating or electron withdrawing group or ZY; R is aryl, aryl lower alkyl, such as benzyl, wherein the aryl group is unsubstituted or substituted and R1 is lower alkyl. In this embodiment, it is most preferred that R3 is hydrogen, an alkyl group, especially methyl, substituted by electron donating group, such as lower alkoxy, (e.g., methoxy, ethoxy and the like), NR4OR5 or ONR4R7 wherein these groups are defined hereinabove.
The most preferred compounds utilized are those of the Formula (II): 
wherein
Ar is aryl, especially phenyl, which is unsubstituted or substituted with at least one electron donating group or electron withdrawing group,
R1 is lower alkyl; and
R3 is as defined herein, but especially hydrogen, loweralkyl, which is unsubstituted or substituted by at least an electron donating group or electron withdrawing group or ZY. It is even more preferred that R3 is, in this embodiment, hydrogen, an alkyl group which is unsubstituted or substituted by an electron donating group, NR4OR5 or ONR4R7. It is most preferred that R3 is CH2xe2x80x94Q, wherein Q is lower alkoxy, NR4OR5 or ONR4R7 wherein R4 is hydrogen or alkyl containing 1-3 carbon atoms, R5 is hydrogen or alkyl containing 1-3 carbon atoms, and R7 is hydrogen or alkyl containing 1-3 carbon atoms.
The preferred R1 is CH3. The most preferred R3 is methoxy.
The most preferred aryl is phenyl.
The most preferred compound includes:
(R)-2-acetamido-N-benzyl-3-methoxy-propionamide,
O-methyl-N-acetyl-D-serine-m-fluorobenzyl-amide;
O-methyl-N-acetyl-D-serine-p-fluorobenzyl-amide;
N-acetyl-D-phenylglycine benzylamide;
D-1,2-(N,O-dimethylhydroxylamino)-2-acetamide acetic acid benzylamide;
D-1,2-(O-methylhydroxylamino)-2-acetamido acetic acid benzylamide.
It is to be understood that the various combinations and premutations of the Markush groups of R1, R2, R3, R and n described herein are contemplated to be within the scope of the present invention. Moreover, the present invention also encompasses compounds and compositions which contain one or more elements of each of the Markush groupings in R1, R2, R3, n and R and the various combinations thereof. Thus, for example, the present invention contemplates that R1 may be one or more of the substituents listed hereinabove in combination with any and all of the substituents of R2, R3, and R with respect to each value of n.
The compounds utilized in the present invention may contain one (1) or more asymmetric carbons and may exist in racemic and optically active forms. The configuration around each asymmetric carbon can be either the D or L form. It is well known in the art that the configuration around a chiral carbon atoms can also be described as R or S in the Cahn-Prelog-Ingold nomenclature system. All of the various configurations around each asymmetric carbon, including the various enantiomers and diastereomers as well as racemic mixtures and mixtures of enantiomers, diastereomers or both are contemplated by the present invention.
In the principal chain, there exists asymmetry at the carbon atom to which the groups R2 and R3 are attached. When n is 1, the compounds of the present invention is of the formula 
wherein R, R1, R2, R3, R4, R5, R6, Z and Y are as defined previously.
As used herein, the term configuration shall refer to the configuration around the carbon atom to which R2 and R3 are attached, even though other chiral centers may be present in the molecule. Therefore, when referring to a particular configuration, such as D or L, it is to be understood to mean the D or L stereoisomer at the carbon atom to which R2 and R3 are attached. However, it also includes all possible enantiomers and diastereomers at other chiral centers, if any, present in the compound.
The compounds of the present invention are directed to all the optical isomers, i.e., the compounds of the present invention are either the L-stereoisomer or the D-stereoisomer (at the carbon atom to which R2 and R3 are attached). These stereoisomers may be found in mixtures of the L and D stereoisomer, e.g., racemic mixtures. The D stereoisomer is preferred.
Depending upon the substituents, the present compounds may form addition salts as well. All of these forms are contemplated to be within the scope of this invention including mixtures of the stereoisomeric forms
The preparation of the utilized compounds are described in U.S. Pat. Nos. 5,378,729 and 5,773.475, the contents of both of which are incorporated by reference.
The compounds utilized in the present invention are useful as such as depicted in the Formula I or can be employed in the form of salts in view of its basic nature by the presence of the free amino group. Thus, the compounds of Formula I forms salts with a wide variety of acids, inorganic and organic, including pharmaceutically acceptable acids. The salts with therapeutically acceptable acids are of course useful in the preparation of formulation where enhanced water solubility is most advantageous.
These pharmaceutically acceptable salts have also therapeutic efficacy. These salts include salts of inorganic acids such as hydrochloric, hydroiodic, hydrobromic, phosphoric, metaphosphoric, nitric acid and sulfuric acids as well as salts of organic acids, such as tartaric, acetic, citric, malic, benzoic, perchloric, glycolic, gluconic, succinic, aryl sulfonic, (e.g., p-toluene sulfonic acids, benzenesulfonic), phosphoric, malonic, and the like.
It is preferred that the compound utilized in the present invention is used in therapeutically effective amounts.
The physician will determine the dosage of the present therapeutic agents which will be most suitable and it will vary with the form of administration and the particular compound chosen, and furthermore, it will vary with the patient under treatment, the age of the patient, the type of malady being treated. He will generally wish to initiate treatment with small dosages substantially less than the optimum dose of the compound and increase the dosage by small increments until the optimum effect under the circumstances is reached. It will generally to found that when the composition is administered orally, larger quantities of the active agent will be required to produce the same effect as a smaller quantity given parenterally. The compounds are useful in the same manner as comparable therapeutic agents and the dosage level is of the same order of magnitude as is generally employed with these other therapeutic agents.
In a preferred embodiment, the compounds utilized are administered in amounts ranging from about 1 mg to about 100 mg per kilogram of body weight per day. This dosage regimen may be adjusted by the physician to provide the optimum therapeutic response. For example, several divided doses may be administered daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation. The compounds of Formula I may be administered in a convenient manner, such as by oral, intravenous (where water soluble), intramuscular or subcutaneous routes.
The compounds of Formula (I) may be orally administered, for example, with an inert diluent or with an assimilable edible carrier, or it may be enclosed in hard or soft shell gelatin capsules, or it may be compressed into tablets, or it may be incorporated directly into the fool of the diet. For oral therapeutic administration, the active compound of Formula I may be incorporated with excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Such compositions and preparations should contain at least 1% of active compound of Formula I. The percentage of the compositions and preparations may, of course, be varied and may conveniently be between about 5 to about 80% of the weight of the unit. The amount of active compound of Formula I in such therapeutically useful compositions is such that a suitable dosage will be obtained. Preferred compositions or preparations according to the present invention contains between about 10 mg and 6 g active compound of Formula I.
The tablets, troches, pills, capsules and the like may also contain the following: A binder such as gum tragacanth, acacia, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, lactose or saccharin may be added or a flavoring agent such as peppermint, oil of wintergreen, or cherry flavoring. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier.
Various other materials may be present as coatings or otherwise modify the physical form of the dosage unit. For instance, tablets, pills, or capsules may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavoring such as cherry or orange flavor. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed. In addition, the active compound may be incorporated into sustained-release preparations and formulations. For example, sustained release dosage forms are contemplated wherein the active ingredient is bound to an ion exchange resin which, optionally, can be coated with a diffusion barrier coating to modify the release properties of the resin.
The active compound may also be administered parenterally or intraperitoneally. Dispersions can also be prepared in glycerol, liquid, polyethylene glycols, and mixtures thereof and in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms.
The pharmaceutical forms suitable for injectable use include sterile aqueous solutions (where water soluble) or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. In all cases the form must be sterile and must be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), suitable mixtures thereof, and vegetable oils. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersions and by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminium monostearate and gelatin.
Sterile injectable solutions are prepared by incorporating the active compound in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the various sterilized active ingredient into a sterile vehicle which contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying the freeze-drying technique plus any additional desired ingredient from previously sterile-filtered solution thereof.
As used herein, xe2x80x9cpharmaceutically acceptable carrierxe2x80x9d includes any and all solvents, dispersion media, coatings, antibacterial and antifungal agent, isotonic and absorption delaying agents for pharmaceutical active substances as well known in the art. Except insofar as any conventional media or agent is incompatible with the active ingredient, its use in the therapeutic compositions is contemplated. Supplementary active ingredients can also be incorporated into the compositions.
It is especially advantageous to formulate parenteral compositions in dosage unit form or ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the mammalian subjects to be treated; each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specifics for the novel dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the active material an the particular therapeutic effect to be achieved, and (b) the limitations inherent in the art of compounding such as active material for the treatment of disease in living subjects having a diseased condition in which bodily health is impaired as herein disclosed in detail.
The principal active ingredient is compounded for convenient and effective administration in effective amounts with a suitable pharmaceutically acceptable carrier in dosage unit form as hereinbefore described. A unit dosage form can, for example, contain the principal active compound in amounts ranging from about 10 mg to about 6 g. Expressed in proportions, the active compound is generally present in from about 1 to about 750 mg/ml of carrier. In the case of compositions containing supplementary active ingredients, the dosages are determined by reference to the usual dose and manner of administration of the said ingredients.
As used herein the term xe2x80x9cpatientxe2x80x9d or xe2x80x9csubjectxe2x80x9d refers to a warm blooded animal, and preferably mammals, such as, for example, cats, dogs, horses, cows, pigs, mice, rats and primates, including humans. The preferred patient is humans.
The term xe2x80x9ctreatxe2x80x9d refers to either relieving the pain associated with a disease or condition or alleviating the patient""s disease or condition.
The compounds of the present invention are useful for treating chronic pain. As used herein, the term xe2x80x9cchronic painxe2x80x9d is defined as pain persisting for an extended period of time, for example, greater than three to six months, although the characteristic signs described hereinbelow can occur earlier or later than this period. Vegetative signs, such as lassitude, sleep disturbances, decreased appetite, lose of taste or food, weight loss, diminished libido and constipation develop.
Types of pain that the compounds of the present invention are especially useful in treating are is acute and chronic pain, particularly non neuropathic inflammatory pain. This include chronic inflammatory pain, e.g. rheumatoid arthritis pain and/or secondary inflammatory osteoarthritic pain.
The compounds of the present invention are administered to a patient suffering from the aforementioned type of pain in an analgesic effective amount. These amounts are equivalent to the therapeutically effective amounts described hereinabove.
The following working examples show the antinociceptive properties in well-defined animal models of acute and chronic pain.
The used substance was SPM 927 which is the synonym for Harkoseride. The standard chemical nomenclature is (R)-2-acetamide-N-benzyl-3-methoxypropionamide.